Celiac disease, with a prevalence around 1% of the general population, is the most common genetically-induced food intolerance in the world. Triggered by the ingestion of gluten in genetically predisposed individuals, this enteropathy may appear at any age, and is characterized by a wide variety of clinical signs and symptoms. Among them, gastrointestinal presentations include chronic diarrhea, abdominal pain, weight loss or failure to thrive in children; but extra-intestinal manifestations are also common, and actually appear to be on the rise. They include a large variety of ailments, such as dermatitis Herpetiformis, anemia, short stature, osteoporosis, arthritis, neurologic problems, unexplained elevation of transaminases, and even female infertility. For the clinician interested in oral diseases, celiac disease can lead to delayed tooth eruption, dental enamel hypoplasia, recurrent oral aphthae. Diagnosing celiac disease requires therefore a high degree of suspicion followed by a very sensitive screening test: serum levels of the autoantibody anti-tissue transglutaminase. A positive subject will then be confirmed by an intestinal biopsy, and will then be put on a strict gluten-free diet, that in most cases will bring a marked improvement of symptoms. Newer forms of treatment which in the future will probably be available to the non-responsive patients are currently being actively pursued.